Novena Rangwala1, David Hackney1, David C. Alsop1
1Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
A model of diffusion signal decay in the transverse plane is proposed and applied to high b-value diffusion-weighted (DW) images of the cervical spinal cord (SC) in vivo. This model assumes that axons within SC are not perfectly aligned and the transverse signal decay is a function of the angle made by the axons with the cord axis. The results show that the average axonal dispersion in the cord is ~10, and decreases to ~6.5 within the posterior funiculus of white matter, indicating that the model is sensitive to regional differences in axon structure.